Finkl, C.W. and Makowski, C., 2020. The Biophysical Cross-shore Classification System (BCCS): Defining coastal ecological sequences with catena codification to classify cross-shore successions based on interpretation of satellite imagery. Journal of Coastal Research, 36(1), 1–29. Coconut Creek (Florida), ISSN 0749-0208.

Coastal classification is a complicated endeavor due to the complexity of coasts and the application of special purpose characterizations for a wide range of tasks. The conundrum of coastal classification in general is also partly related to variable definitions and uses of common terms such as coast, coastline, shore, shoreline, and seashore. This research effort was not aimed at replacing extant systems but rather investigating the possibility of using the new Biophysical Cross-shore Classification System (BCCS) to define or classify cross-shore ecological successions in coastal belts based visual analytics and cognitive interpretation of satellite imagery. Approximately 200 coastal images from equatorial to polar regions showed that specific types of ecological successions were repetitive and could be organized by dominant characteristics. Certain ecological characterizations were so prominent and common that they became identified as Archetypes, which included Barrier, Beach, Beach Ridge, Cliff, Coral Reef, Delta, Dune, Flat, Ice, Lagoon, Mountain, Rock, Till (Glacial Material), Upland, and Wetland. When several archetypes are sequentially linked together based on the cross-shore ecological interpretation of the imagery, a generalized or idealized common master sequence is created and deemed the Dominant Catenary Sequence (DCS; e.g., Beach-Dune-Wetland). The more detailed Coastal Ecological Sequence (CES) of a coastal belt, which is presented as a codification sequence, can be formulated by cognitively linking the Dominant Catenary Sequence with a numbered shore-parallel shape distinction and subscripted sub archetypes that further refine the archetypes present in the DCS. Overall, the BCCS was found to be an effective method for the classification of cross-shore ecological successions in coastal belts. Descriptive headers, extended captions, and Coastal Ecological Sequences are provided for randomly selected satellite images, with some examples shown in this paper.

Nahirnick, N.K.; Costa, M.; Schroeder, S., and Sharma, T., 2020. Long-term eelgrass habitat change and associated human impacts on the west coast of Canada. Journal of Coastal Research, 36(1), 30–40. Coconut Creek (Florida), ISSN 0749-0208.

Eelgrass (Zostera marina) forms a critical nearshore marine habitat in temperate coastal ecosystems. For three small estuaries in the Southern Gulf Islands of British Columbia, changes in eelgrass area coverage and shape index (over the period of 1932–2016) were assessed using historical aerial photographs and unoccupied aerial system (UAS) imagery. In addition, changes in eelgrass area and shape index were evaluated in relation to landscape-level coastal environmental indicators, namely shoreline activities and alterations and residential housing density. All three eelgrass meadows showed a deteriorating trend in eelgrass condition; on average, eelgrass area coverage decreased by 45.1%, while meadow complexity as indicated by the shape index increased by 66.3%. Shoreline activities (boats, docks, log booms, and armoring) and residential housing density increased markedly at all sites over the study period and were strongly correlated to eelgrass area coverage and shape index. Changes in these landscape-level indicators over this period corroborate the observed decline in eelgrass habitat condition, because they suggest an overall deterioration of coastal environmental health in the Salish Sea due to increased use of the coastal zone, as well as declines in water quality due to urbanization.

Mattheus, C.R.; Ramsey, K.W., and Santoro, J.A., 2020. Evaluating continental shelf seabed-elevation changes from archived sediment-core records: Issues with vertical positioning and implications for integration with subsurface geophysics. Journal of Coastal Research, 36(1), 41–53. Coconut Creek (Florida), ISSN 0749-0208.

Sediment-core records from the sand ridge–dominated inner continental shelf of Delaware were studied to address impacts of seabed morphodynamics and positioning accuracy on data integration. Differences in vertical seafloor position were calculated for 366 point locations from core-report information (from 1984 to 2017) and a 2007 echo-sounding data set. Resulting net-change metrics were evaluated against seafloor geology and shelf zonation based on morphology. While gravelly units trended slightly towards net-elevation loss at an average of –0.2 m, shoal sand bodies averaged net-zero change. Almost 90% of change metrics fell within ±2 m, approximating the average relief of major shelf bed forms. A pairwise analysis of variance test revealed no statistically significant difference in vertical change at the 0.05 confidence level, based on geology, nor based on shelf zonation. Vertical positioning inaccuracies and reporting issues are primary concerns, even after quality control eliminated over 20% of available core records (total n = 466) because of undocumented tidal correction and vertical datum conversion procedures, which could have resulted in vertical offsets on the order of 2 m. Within the remaining data set, questionable values were recognized by a GIS-based buffer analysis, using core age and an assumed 10 m/y rate of bed-form migration to isolate metrics in disagreement with seafloor morphology. Data from three coring projects consistently overvalued net-change predictions, raising questions about their utility as stratigraphic benchmarks for ground-truthing seismic data. Accurate constraint of core depth is crucial for offshore resource allocation and infrastructure planning efforts, highlighting the importance of investigating vertical data resolution and addressing reporting inaccuracies.

Gao, G.-F.; Zhang, X.-M.; Li, P.-F.; Simon, M.; Shen, Z.-J.; Chen, J.; Gao, C.-H., and Zheng, H.L., 2020. Examining soil carbon gas (CO₂, CH₄) emissions and the effect on functional microbial abundances in the Zhangjiang Estuary Mangrove Reserve. Journal of Coastal Research, 36(1), 54–62. Coconut Creek (Florida), ISSN 0749-0208.

Mangrove soil is regarded as an important source of CO₂ and CH₄ because of its large carbon pools. However, little is known about the magnitudes of CO₂ and CH₄ emitted from mangrove soils and their relationships with functional microbial abundances. Here, a field experiment was conducted in Zhangjiang Estuary Mangrove from August 2014 to September 2016. Soils dominated by species Kandelia obovata (KO), Avicennia marina (AM), and bare mudflat (Mud) were randomly established, respectively. The results showed that soil of the Zhangjiang Estuary Mangrove wetland is a significant source of CH₄ (ranging from –35.36 to 2822.52 µg m^–2 h^–1) and CO₂ (ranging from –28.45 to 116.26 mg m^–2 h^–1), with a significant spatial and seasonal variation pattern. The soil CH₄ emissions were positively correlated to the mcrA gene abundance and organic matter content. Meanwhile, the 16S rRNA and ANME-pmoA gene abundances were positively correlated to the soil CO₂ emissions. When considering only the soil-atmosphere exchange of carbon gas, soil CO₂ emission was the major contributor to the global warming potential, accounting for 64.66%–96.11%. The profound variations of soil CH₄ and CO₂ emissions may imply the important role of dominant mangrove vegetation on soil microbes and carbon gas emissions.

Wu, B.; Jin, H.; Gao, S.; Xu, J., and Chen, J., 2020. Nutrient budgets and recent decadal variations in a highly eutrophic estuary: Hangzhou Bay, China. Journal of Coastal Research, 36(1), 63–71. Coconut Creek (Florida), ISSN 0749-0208.

Hangzhou Bay is one of China's most eutrophic waterbodies, yet water quality observations within the bay are few, and the estuary's nutrient dynamics are poorly understood. Five cruises (summer, autumn, winter, spring) were conducted in Hangzhou Bay and adjacent waters between July 2006 and November 2007 and in August 2018. A steady-state box model was also constructed to estimate summer and winter nutrient fluxes. The results show that the spatial distributions and temporal variations of nutrients within the bay are significantly influenced by not only direct inputs from rivers around the bay but also the Changjiang River plume to the north. Bay concentrations of nitrate (), dissolved inorganic phosphorus (DIP), and dissolved silicate (DSi) were quite high throughout the year, especially in the head of the bay. Relative to concentrations measured in 1981–1982, estuarine concentrations of and DIP had increased, whereas DSi had been stable. The model results indicate that riverine discharge is the major source of nutrients to Hangzhou Bay. In both summer and winter, nutrients were exported from the bay to the East China Sea. The fluxes of , dissolved inorganic nitrogen (DIN), DIP, and DSi were higher in summer than winter, but the flux of ammonium was higher in winter. Nutrient fluxes to Hangzhou Bay observed here during 2006–2007 are much higher than those observed in the 1980s. Additionally, nutrient abundances in Hangzhou Bay are significantly higher than those reported for other coastal embayments in China. The difference in algal blooms inside and outside the bay is possibly due to the difference in turbidity or the hydrological conditions.

Kelly, J.T. and Gontz, A.M., 2020. Rapid assessment of shoreline changes induced by Tropical Cyclone Oma using CubeSat imagery in southeast Queensland, Australia. Journal of Coastal Research, 36(1), 72–87. Coconut Creek (Florida), ISSN 0749-0208.

Tropical Cyclone Oma hit the SE Queensland coast of Australia in February 2019. Significant wave heights exceeding 10 m were further amplified by a king tide. Satellite remote sensing of pre- and post-Oma shoreline positions was performed because storms hindered the ability to acquire field-based data. The high spatial and temporal resolution of PlanetScope imagery enabled mapping of the high water line (HWL), which was used as a shoreline indicator across 200 km of shoreline. Given that this is the first use of PlanetScope imagery to map shoreline positions, the positional uncertainty was assessed. Comparison to a temporally coincident, LIDAR-derived mean high water (MHW) shoreline at a distant site showed an average horizontal offset of 9 m with the HWL shoreline. The Oma-affected shoreline uncertainty ranged between ±13.86 and 23.28 m, primarily influenced by the geometric accuracy of the data used, as well as the pixel size of the imagery and the horizontal offset between the HWL and MHW elevations. The net shoreline movement (NSM) was calculated every 200 m along the study area by the Digital Shoreline Analysis System. Only transects with NSM values greater than the uncertainty of their associated shoreline compartment were used to assess change. The spatial distribution of erosion and accretion was similar across the SW–NE-oriented shorelines as the southern ends of Fraser Island and the Cooloola Sand Mass eroded while their northern ends prograded. Wave data shows that the wave direction rapidly shifted 56° in an anticlockwise direction during Oma. Wave propagation came primarily from the SE, and the direction of longshore transport likely turned northward, leading to the shoreline rotation observed in the imagery. This study demonstrates the significant improvement on assessments of regional-scale shoreline changes in the aftermath of an episodic event using new satellite products.

Moore, G.E.; Burdick, D.M., and Payne, A.R., 2020. Determining how soil amendments enhance the recovery of Ammophila breviligulata following dune die-off events in coastal New England. Journal of Coastal Research, 36(1), 88–93. Coconut Creek (Florida), ISSN 0749-0208.

Coastal dunes are valued for habitat provision and flood protection. The dominant dune plant in New England, American beachgrass (Ammophila breviligulata) stabilizes dunes by trapping sand and slowing erosion. The system's natural mechanism to stabilize sediment and protect coasts from erosion may be threatened by die-off, a rapidly spreading blight affecting coastal dunes from Maine to Virginia. To determine whether soil amendments could help mitigate die-off and aid recovery, fertilizer and lime were applied to dunes at three sites that had recently been defoliated by die-off and subsequently replanted. The lime+fertilizer treatment resulted in a significantly greater percentage of live plants and percentage of cover of A. breviligulata, as well as greater total plant cover. The combined application of lime and fertilizer may hasten recovery from die-off and improve restoration success in the region.

Millán-Aguilar, O.; Nettel-Hernanz, A.; Hurtado-Oliva, M.Á.; Dodd, R.S.; Flores-Cárdenas, F., and Manzano-Sarabia, M., 2020. Landscape metrics and conservation status of five mangrove wetlands in the eastern Gulf of California margin. Journal of Coastal Research, 36(1), 94–102. Coconut Creek (Florida), ISSN 0749-0208.

Ecological significance and relevance of mangrove wetlands has been widely highlighted worldwide. Nevertheless, human-derived impacts and climate variability are increasing threats to these ecosystems in the last decades. Mangroves from Sinaloa (Mexico) integrate a large wetland corridor and provide several ecosystem services; however, diverse stressors could be increasing their vulnerability and associated biodiversity. The conservation status of five mangrove wetlands in this region was assessed through remote sensing techniques, landscape metrics, official databases and in situ records. In general, a decrease on mangrove cover was observed, excepting Estero de Urías and Ceuta, while aquaculture increased in all sites, with a greatest coverage in Santa María-La Reforma (increased 2057 ha in 18 years). The largest annual rate of change was observed in Huizache-Caimanero (–0.99%). Although conservation programs exist, there are signs of deterioration of mangrove wetlands according to this study.

Zhan, Y.; Aarninkhof, S.G.J.; Wang, Z.; Qian, W., and Zhou, Y., 2020. Daily topographic change patterns of tidal flats in response to anthropogenic activities: Analysis through coastal video imagery. Journal of Coastal Research, 36(1), 103–115. Coconut Creek (Florida), ISSN 0749-0208.

The natural geomorphology of muddy coastal zones can easily change in a short period of time, especially under the influences of coastal engineering. However, although short-term morphological change patterns can affect the establishment of salt marsh vegetation on bare tidal flats, these patterns are rarely studied. This work presents the results of an investigation of the daily variation pattern of tidal flats in response to anthropogenic activities by using microtopographic units (areas of local uplift) as indicators. The changes exhibited by these microtopographic units (microunits) were monitored by a coastal video system with two high-definition cameras for 29 days. The results show that microunits initially tended to form near the sluice gate, spread throughout the study area in the alongshore direction, and then gradually disappeared with increase in time. Finally, the geomorphology of the tidal flat recovered to the state before the scouring event in only a few days. A statistical analysis of the areas of individual microunits showed that they tended to become miniaturized and fragmented. The number of small microunits (area between 1 and 10 m²) increased significantly during the recovery period under the influence of the tidal current. This dynamic equilibrium was also observed through an analysis of one region of interest, thereby illustrating an iterative equilibrium by shifting between fragmentation and flattening during the recovery period. As a result, this work presents the first usage of a coastal video system to monitor tidal flats and gives several contributions to prove that microtopographic units can be regarded as useful indicators for studying the daily change patterns of tidal flats in response to anthropogenic activities, thereby providing an alternative method for analyzing the morphological changes corresponding to other short-term events, such as storms.

Fang, K.; Wang, H.; Sun, J.; Zhang, J., and Liu, Z., 2020. Including wave diffraction in XBeach: Model extension and validation. Journal of Coastal Research, 36(1), 116–127. Coconut Creek (Florida), ISSN 0749-0208.

An extended version of the XBeach model is presented in this paper to improve the accuracy of predicted wave and current fields and sandy beach evolution in scenarios in which wave diffraction takes effect. Following the approach successfully implemented in the Simulating Waves Nearshore (SWAN) spectral wave model, a diffraction parameter is introduced into the wave action balance equation in XBeach to take wave diffraction into account. An alternative wave breaking index and the formulation for the critical velocity are also tested in the extended model to achieve better model–data agreement. The extended model is validated by comparing the simulation results with those of physical tests for fixed and movable sea beds. The computed wave height, wave-induced current field, and beach evolution are found to be in satisfactory agreement with the measurements, and the numerical modeling capacity of the extended model to represent wave diffraction effect is thus demonstrated.

Liu, Y.; Li, X., and Hou, X., 2020. Spatiotemporal changes to the river channel and shoreline of the Yellow River Delta during a 40-year period (1976–2017). Journal of Coastal Research, 36(1), 128–138. Coconut Creek (Florida), ISSN 0749-0208.

The coastal zone is a sensitive region affected by both human activities and climate change. The shoreline is a crucial component of coastal zones. Shoreline monitoring research has a vital role in managing and protecting coastal ecosystems and communities. This study focuses on measurements of morphological change in the Yellow River channel and the Yellow River Delta (YRD) shoreline during a 40-year period. The lower reaches of the Yellow River continuously changed because of silting, stretching, lifting, swinging, and avulsion, to ultimately, changing course. The location of the mouth of the Yellow River was directly influenced by the swinging and the artificial avulsion. Overall, the shoreline expanded seaward at a decreasing rate over time, but it exhibited distinctively different patterns in two subregions (Diaokou and Qingshuigou). The shoreline in Diaokou displayed a trend of retreating inland, whereas the shoreline in Qingshuigou expanded rapidly towards the sea. The rate of change was greatest near the river mouth. An upward trend in the shape index was found across the YRD and its subregions, reflecting the shoreline becoming more complex over time. Human activities will become an increasingly important factor affecting the development and evolution of the YRD. This study should be useful for coastal engineers, coastal managers, and policy makers in the YRD.

Lu, Z.; Zhan, X.; Guo, Y., and Ma, L., 2020. Small-scale effects of offshore wind-turbine foundations on macrobenthic assemblages in Pinghai Bay, China. Journal of Coastal Research, 36(1), 139–147. Coconut Creek (Florida), ISSN 0749-0208.

In recent years, offshore wind farms in China have developed rapidly, especially in SE coastal regions. The construction of wind-turbine foundations (WTFs) introduces new artificial structures into coastal ecosystems, influencing the surrounding macrobenthos. Small-scale effects on macrobenthic assemblages around a high-rise cap pile WTF in Pinghai Bay, China, were investigated in November 2017 and May 2018, along SW and SE gradients. The macrobenthic abundance increased from 220 ± 92 individuals (ind) m^–2 at 200 m to 547 ± 103 ind m^–2 at 25 m from the foundation, and the species number increased from 8 ± 3 at 200 m to 16 ± 6 per sample at 25 m from the foundation, whereas the biomass decreased from 17.2 ± 2 g m^–2 at 200 m to 3.1 ± 1.4 g m^–2 at 25 m from the foundation. The macrobenthic abundance increased by 94.75% compared with that before the WTF construction. Abundance significantly increased from 179 ± 115 to 463 ± 255 ind m^–2 for Annelida, from 62 ± 56 to 99 ± 77 ind m^–2 for Arthropoda, and from 4 ± 3 to 22 ± 25 ind m^–2 for Echinodermata. However, the abundance of Mollusca decreased from 65 ± 100 to 14 ± 22 ind m^–2. Thus, it is likely that most macrobenthos were able to recover quickly after the deployment of WTF, whereas more time might be needed for Mollusca to recover. There was also an obvious shift in species dominance, with Annelida becoming the dominant group (73.28–77.78%) in the macrobenthic community.

Liu, C. and Huang, Z., 2020. A flexible membrane breakwater with a piezoelectric layer for providing harborage and wave-energy conversion. Journal of Coastal Research, 36(1), 148–156. Coconut Creek (Florida), ISSN 0749-0208.

Integration of wave-energy converters with coastal structures provides a way to make wave-energy utilization economically viable. This theoretical study examines a piezoelectric membrane system that serves as a breakwater and a wave-energy harvester. The system is in the form of a piezoelectric layer built into a flexible membrane wave barrier. Series resistor-inductor-capacitor electric circuits are used to obtain electrical output power from ocean waves through the piezoelectric layer. This type of piezoelectric membrane system is proposed for providing harborage and wave-energy extraction at marinas and small boat harbors. Use of an eigenfunction expansion method, solutions to the wave-scattering problem, the calculation of the deflection of the piezoelectric membrane, and an analytical expression for the electric-power output per unit surface area of the piezoelectric layer (output power density) are described. The output power density can reach its maximum value at an optimum resistance, which increases with the thickness and surface area of the piezoelectric layer and decreases with wave frequency. At the optimum resistance, the maximum power output density and the minimum transmission coefficient occur at the same critical frequency, which is controlled by the dimensions and initial tension of the piezoelectric membrane. The surface area and the inductance of the piezoelectric layer have little effect on the output power density, which increases with the thickness of piezoelectric layer nearly linearly.

Gong, J.; Li, Y.; Jiang, F.; Hong, Z., and Yu, D., 2020. Maneuvering simulation and study on the effect of hull attitude on maneuverability of trimarans by OpenFOAM. Journal of Coastal Research, 36(1), 157–173. Coconut Creek (Florida), ISSN 0749-0208.

Based on open-source code OpenFOAM, the turn and zigzag maneuvers of the trimaran with hull attitude free and fixed are simulated at different Froude numbers in calm water. By the simulation results, the effect of hull attitude on the maneuver characteristics of the trimaran is analyzed and discussed. Two trimaran models are used in this paper for simulation. First, the grid uncertainty test about the turn and zigzag maneuver in calm water is carried out, and the computed results of turn and zigzag maneuvers in calm water are compared with the experimental results to validate the numerical method. Then, the simulation result with free hull attitude is compared with that with fixed hull attitude. The result demonstrates that the hull attitude has significant effect on the maneuverability of the trimaran, especially when the Froude number gets larger and the longitudinal position of the side hulls is in the middle of the center hull.

Almarshed, B.; Figlus, J.; Miller, J., and Verhagen, H.J., 2020. Innovative coastal risk reduction through hybrid design: Combining sand cover and structural defenses. Journal of Coastal Research, 36(1), 174–188. Coconut Creek (Florida), ISSN 0749-0208.

Worldwide, sand dunes and hard coastal structures help to minimize loss of lives and property from storm impact and flooding along or behind coastlines. Both sand dunes and hard coastal structures have their benefits and shortfalls in terms of protective capacity, cost, flexibility, and impact to coastal systems. Combining these two inherently different coastal risk reduction measures into a single hybrid system can preserve some of the individual benefits of each while creating an Engineering-with-Nature^™ system that fulfills the requirements of high levels of protection, adaptability to future challenges related to climate change, sustainability, and pleasing natural aesthetics. Although such hybrid systems have the potential to become viable alternatives to conventional coastal risk reduction schemes, there are still many unknowns related to the interaction between the soft and hard structural components and their effectiveness in storm surge mitigation and flood prevention that require targeted research efforts to create acceptable design guidelines. Specifically, the combination of hard and soft alternatives into a single structure has not been studied in detail. Here, hybrid coastal risk reduction systems consisting of traditional hard structures (levees, revetments, and sea walls) covered by sand layers attempting to mimic dunes are investigated. It is emphasized that these sand covers can look like natural dunes, but they cannot evolve like natural dunes in the long term due to spatial constrictions along developed coasts and lack of natural sediment supply in eroding coastal systems. Just like any engineered beach and dune system, these hybrid structures require episodic maintenance nourishment, particularly after storm impact. The present overview covers design advances and issues related to both hard structures and engineered sand dunes for coastal risk reduction and investigates existing hybrid approaches. Future research goals to better understand hybrid coastal risk reduction systems and to create applicable design guidelines are discussed.

Nguyen, T.H.T.; Park, S.W., and Ahn, J., 2020. Numerical method to determine upstream scour slope in relation to turbulence and particle movement. Journal of Coastal Research, 36(1), 189–195. Coconut Creek (Florida), ISSN 0749-0208.

Several studies have been conducted to investigate the behavior of scour hole, which happens naturally at the end of the bed protections in the streams and rivers, because this phenomenon can result in the instability or destruction of man-made structures in the area. Some formulas or equations were introduced to calculate the upstream scour slope, one of the most important scour properties, but the application shows some difficulty because of the lack of data. This paper presents a simple but reasonable method to find upstream scour slope with the employing of a numerical simulation, in particular by considering the relationship between turbulence and particle movement.

Yin, Z.; Wang, Y., and Jia, Q., 2020. Hydrodynamic characteristics of a pneumatic breakwater with combined wave–current actions: A numerical investigation. Journal of Coastal Research, 36(1), 196–203. Coconut Creek (Florida), ISSN 0749-0208.

A pneumatic breakwater is a new type of coastal protection structure with mobility and environment-friendly advantages. A series of physical experiments with two-dimensional (2-D) numerical modeling was conducted to investigate the hydrodynamic characteristics of a pneumatic breakwater under wave–current action. The numerical model consists of the Reynolds-averaged Navier-Stokes (RANS) equations, the renormalization group (RNG) k-ε turbulence model, and the volume of fluid (VOF) method. An additional mass source term was added to the continuity equation to generate the desired air bubbles, and it was well validated with the related experimental data. The wave transmission coefficient (K_t) of a pneumatic breakwater was explored in relation to the incident wave height (H_i), wave period (T), air flow rate per unit width (q), and depth-averaged current velocity to wave phase velocity ratio (U/C) in both wave-alone and wave–current fields. The results indicated that K_t of the pneumatic breakwater in a wave-alone field increased with increasing H_i and T and decreased as q increased. Additionally, K_t of waves following a current increased with increasing U/C, while that of waves opposing a current increased up to a certain value before decreasing with U/C. Finally, the wave energy flux parameter was used to investigate the energy damping effect of the pneumatic breakwater in a wave–current field.